If you don’t already know the story of amateur sailor Donald Crowhurst, expect for some doom and gloom in The Mercy. And if you don’t want to know what’s going to happen at the end, don’t google him or click on the link above.

This is a heavily dramatised biopic designed to heave on the heartstrings by swinging from one extreme to another. In order to ensure we’re invested in Crowhurst’s journey, we are presented with many irritatingly picture-perfect, idyllic, sun soaked, English summer days showing his perfect marriage to his perfectly beautiful wife (who never cracks a frown, and has immaculate hair at even the unlikeliest of moments) and perfect children, having an almost perfect time of it. It’s all a tad two dimensional, which is probably designed as such to ensure a big contrast with what’s to come, but this is a real life story and we know real life isn’t like that.

But then Crowhurst puts out to sea in his ill-prepared boat, with practically no experience. We’re alone with Colin Firth and the ocean and this is where it gets good.

Firth is a brilliant actor and this portrayal is no exception. Watching him grapple with the life-threatening ordeals the raw wilds of nature throw at him, is both gripping, realistic and fascinating. It’s pretty miserable of course, but totally believable and there are some utterly breathtaking scenes that make us feel immersed, simulating as close as the cinema screen has ever taken us, the experience of terrifying, unrelenting, deep sea storms in a small vessel. For this reason, this is worth a watch especially for those of us who have ever been at sea, seriously sailed or are just fascinated by the oceans’ power. There are even some laughs to be had along the way.

Rachel Weisz is the other big name in the movie, playing Donald’s wife Claire. It’s interesting how the film industry can be so selective in its approach to “getting it right”. A woman who lived by the windy, sunny, English coast, in the 1960’s, with several children, little money and seven months of considerable stress and single parenting (and no access to botox or quality modern beauty products) is likely to have some lines, wrinkles and imperfections to say the least. Not so here. Once again the industry is insidiously telling women by presenting these ideals in its casting of real-life people, that it’s fine for men to age, but women should appear ethereal.

This is an interesting story, somewhat of a moral cautionary tale for grown-ups, but it would be better told if Crowhurst’s home life was more realistic – not Enid Blyton meets Hollywood.